Laundry detergent compositions containing polyesters have been widely disclosed in the art.
DE 10 2007 013 217 A1 and WO 2007/079850 A1 disclose anionic polyesters that may be used as soil release components in washing and cleaning compositions.
DE 10 2007 005 532 A1 describes aqueous formulations of soil release oligo- and polyesters with a low viscosity. The aqueous formulations may for example be used in washing and cleaning compositions.
EP 0 964 015 A1 discloses soil release oligoesters that may be used as soil release polymers in detergents and that are prepared using polyols comprising 3 to 6 hydroxyl groups.
EP 1 661 933 A1 is directed to at room temperature flowable, amphiphilic and nonionic oligoesters prepared by reacting dicarboxylic acid compounds, polyol compounds and water-soluble alkylene oxide adducts and their use as additive in washing and cleaning compositions. The primary focus of this document is on higher stability polymers and higher compatibility polymers for liquids. The performance of the polymers compared to the then state of the art for polyester soil release polymers is not derivable from this document. The performance data even for the fresh polymer (oligoester) is not very impressive because it was apparently not used as would be conventional for a soil release polymer on a fabric prewashed in the same composition. Thus the skilled worker can derive little information about the likely practical in wash performance benefit of the claimed oligoesters
However, many of the polyesters described in the prior art are in need of improved stability in an alkaline environment, particularly when triethanolamine is also present. This material is useful to neutralise anionic surfactants for use in alkaline compositions, especially linear alkyl benzene sulphonate. Triethanolamaine also catalyses the alkaline hydrolysis of many polyesters otherwise suitable for use in detergents thereby losing soil release power. Furthermore, especially in alkaline heavy duty washing liquids polyesters often show turbidity upon incorporation.
GB 1 466 639 describes heavy duty liquid detergent compositions containing nonionic surfactants, ethanolamine-neutralized anionic surfactants, free ethanolamines and a polymeric soil release agent. The nonionic surfactant should be present in excess over the anionic to boost oily soil removal. At column 6 lines 2 to 5 it is pointed out that soil release polymers of the type claimed deposit under rinse conditions. In the test protocol the composition is applied via an unspecified prewash process. It appears that the “prewash” is needed to get the effect (polyester prewashed with the polymer containing compositions outperform those prewashed with the same composition without the polymer). It is common general knowledge that these early types of soil release polymer did not deposit well during the wash. As a result they were not commercially useful. GB 1 4 66 639 also explains that the compositions comprising the polymers were storage stable with triethanolamine. At several places it also states that they were equally storage stable with or amines etc; for example at Column 9 lines 36 to 43. This is not surprising because in contrast to the polymers with polyethoxylated end modifications described in the already discussed prior art this earlier type of polymers with the polyethoxylation embedded inside the polymer midblock rather than being at the end(s) does not fall apart to make non functional polymers if hydrolysed. Thus, the polymers in GB 1 466 639 can be viewed as compromising performance but having greater stability than the more recent polyester based soil release polymers developed mainly for powders applications. Starting from this prior art the skilled person does not require a more stable polymer. Instead, they must seek a higher performing polymer.
Therefore, it was the object of the present invention to provide compositions comprising triethanolamine in combination with selected new polyesters which have an advantageous stability in alkaline environment, possess a beneficial solubility and advantageously are clearly soluble in alkaline compositions such as alkaline heavy duty washing liquids and also possess advantageous soil release properties.